Global demand for antimicrobial cleansing compositions is on the rise. Antimicrobial soap bars and cleansers for hand and body are increasingly being preferred by consumers.
Antimicrobial cleansing compositions containing an oligodynamic metal like silver, copper or zinc are very effective against a variety of bacteria. Silver is used most widely. However some metals, especially silver, are particularly prone to destabilisation when exposed to high pH, heat and strong sunlight which cause darkening or agglomeration or under extreme conditions, even phase separation.
Usually such metals are included at ppm or ppb (parts per million/parts per billion) levels which make it imperative to preserve their activity.
WO2007054227 A1 (Lanxess Deutschland GmbH) discloses silver containing macroporous chelating ion exchange resin comprising a copolymer of a monovinyl monomer like styrene and an aromatic divinyl monomer such as divinylbenzene. The copolymer is functionalized with aminoalkylphosphonic groups or with iminodiacetic acid groups. It lends storage stability and delivery to silver.
A journal article entitled “Synthesis of nanosized silver particles by chemical reduction method” [Materials Chemistry and Physics 64 (2000) 241-246] discloses that PVP and PVA are protective agents for silver colloids from agglomeration and they can be used during manufacture of nano silver. PVP is said to prolong the stability.
US2006240122 A1 (Miner Edwin) discloses that polypectate and EDTA can be used to stabilise silver and prolong its antimicrobial effect. It is also disclosed that chelated silver disperses better than non-chelated silver. The polypectate chelates with calcium and magnesium ions. The silver complex is prepared by first forming an ammoniacal silver nitrate mixture. The application also discloses a liquid antiseptic having water, silver ions, polypectate and EDTA.
In KR20070059786A (Bioplus Co Ltd) is disclosed a composition for disinfecting teat of an animal. The composition includes silver nanoparticles and a polymer stabilizer such as polyvinylpyrrolidone, (1-vinyl pyrrolidone)-acrylic acid copolymer, polyoxyethylene stearate and (1-vinylpyrrolidone)-vinyl acetate copolymer.
US4680131 (BUSCH ALFRED [BE] ET AL) discloses Laundry detergent compositions comprising from about 2% to about 60% of organic surfactant, from about 1% to about 20% of smectite-type clay selected from saponites, hectorites and sodium and calcium montmorillonites, from about 0.001 to about 0.4 mmoles % of copper precomplexed with an aminopolycarboxylate sequestrant, and from about 0.5% to about 50% of peroxygen bleaching agent and/or peroxygen bleach percursor therefor. The compositions provide improved bleaching activity.
US2013/102515 (HUEFFER STEPHAN [DE] ET AL) discloses formulations comprising (A) at least one compound selected from aminocarboxylates and olyaminocarboxylates, and salts and derivatives thereof, (B) at least one zinc salt, and (C) at least one homopolymer or copolymer of ethyleneimine.
There still remains an unmet need for faster-acting and efficacious antimicrobial products.